What are PcG cells?

The Polycomb group (PcG) of proteins defines a subset of factors that physically associate and function to maintain the positional identity of cells from the embryo to adult stages. PcG has long been considered a paradigmatic model for epigenetic maintenance of gene transcription programs.

What is PcG in biology?

Polycomb group (PcG) proteins are a set of general transcriptional repressors essential for development in many organisms. They are best known as repressors that restrict Hox gene expression along the anterior–posterior animal body axis.

How are the Polycomb group PcG proteins involved in gene expression?

Polycomb group (PcG) proteins are critical regulators of gene expression originally discovered through genetic screens in Drosophila [1,2]. During development, PcG proteins and the opposing Trithorax group proteins cooperate to establish transcriptional patterns of key regulators, such as Hox (homeobox) genes [3–6].

What do Polycomb proteins do?

Polycomb (Pc) proteins play roles in gene silencing through different mechanisms. These proteins act in complexes and govern the histone methylation profiles of a large number of genes that regulate various cellular pathways.

What do you need to know about PcG proteins?

This recent review give a great look more of the lesser known attributes of the PcG proteins. This review is for a reader who known about what PcG proteins are, but wants some more detailed information on some key components. Sauvageau, M., and Sauvageau, G. (2010). Polycomb group proteins: multi-faceted regulators of somatic stem cells and cancer.

How are PCG and Polycomb group proteins related?

In contrast overexpression of PcG proteins correlates with the severity and invasiveness of several cancer types. The mammalian PRC1 core complexes are very similar to Drosophila. Polycomb Bmi1 is known to regulate ink4 locus (p16 Ink4a, p19 Arf ).

Why are PcG proteins important for chromatin differentiation?

These proteins have been the subject of intense study as it is clear that they are vital for maintenance of cell-type identity, differentiation, and disease by creating and maintaining repressive chromatin environments. Most PcG proteins form two major polycomb repressive complexes (PRC): PRC1, and PRC2.

How does the PcG repressive complex work together?

These complexes work together to carry out their repressive effect. PcGs proteins are evolutionarily conserved and exist in at least two separate protein complexes; the PcG repressive complex 1 (PRC1) and the PcG repressive complex 2–4 (PRC2/3/4).